Project on Concrete Mix Design for various grades of Concrete

Calculate the Concrete Mix Design for M35 grade concrete with fly ash & M50 grade concrete without Fly ash

Part I

Aim: To determine the design mix proportions for the M35 grade of concrete with fly ash.

Procedure: The following are the step that are used to prepare the design mix few data are assumed

I. Stipulations for proportioning

1. Grade designation : M35
2. Type of cement : OPC 43 grade conforming to IS 8112
3. Maximum nominal size of aggregate : 20mm
4. Minimum cement content : 320 kg / m ^ 3 ( From Table 5 of IS 456 : 2000 Exposure condition )
5. Maximum water - cement ratio : 0.45 ( From Table 5 of IS 456 : 2000 - Exposure condition )
6. Workability : 100 mm ( slump value for pumpable concrete )
7. Exposure condition : Severe ( for reinforced concrete )
8. Method of concrete placing : Pumping
9. Degree of supervision : Good
10. Type of aggregate : Crushed angular aggregate
11. Maximum cement content : 450 kg / m ^ 3
12. Chemical admixture type : Super plasticizer
13. Type of mineral admixture : Fly ash confirming to IS3812 (Part1)

II . Data for materials :

1. Cement used : OPC 43 grade conforming to IS 8112
2. Specific gravity of cement : 3.15
3. Specific gravity of fly ash : 2.2
4. Chemical admixture : Super plasticizer conforming to IS 9103
5. Specific gravity of : Coarse aggregate : 2.74 , Fine aggregate: 2.74
6. Fine aggregate confirming to grading zone I of table 4 of IS383.

III . Target Strength for Mix proportioning :

f'ck fck + 1.65 S

Where , f'ck = Target average compressive strength at 28 days

fck Characteristic compressive strength at 28 days

S = Standard deviation

From Table 2 of IS 10262: 2019, standard deviation , S = 5 N / mm ^ 2

Target strength = 35 + 1.65 X 5 =43.25 N / mm ^ 2

IV . Selection of Water - cement ratio :

From Graph 1 IS10262:2019 W/C Ratio is = 0.39

From Table 5 of IS 456: 2000 for severe exposure, maximum water – content is 0.45

0.39<0.45 , hence O.K

V. Selection of Water content

From Table 4 of IS 10262 : 2019 , maximum water content for 20mm aggregate =186 litre (for 25mm to 50mm slump value)

Estimated water content for 100 mm slump = 186 + 6/100 * 186 = 197 litre

As superplasticizer is used , the water content can be reduced up to 23 %

Hence the arrived water content = 197 * 0.77 = 152 litre

VI . Calculation of Cement Content :

Water - cement ratio = 0.39

Cement content = 152 / 0.39 = 390 kg / m ^ 3

With 10% increase in cementitious material

cementitious material content=390*1.1=429 kg / m ^ 3

water content=152 kg / m ^ 3

so w/c ratio =152/429=0.354

Fly ash as 30% of total cementitious material=429*0.3=129 kg / m ^ 3

Cement (OPC)=429-129= 300 kg / m ^ 3

From Table 5 of IS 456 minimum cement content for severe exposure condition = 320 kg / m ^ 3

429 kg / m ^ 3 > 320 kg / m ^ 3 , hence ok

VII . Proportion of Volume of coarse aggregate and Fine aggregate content :

From Table 5 of IS 10262 : 2019 , Volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate ( Zone I ) for water - cement ratio of 0.5 = 0.6

In the present case the water cement ratio is 0.354

Therefore , the volume of coarse aggregate needs to be increased to decrease the fine aggregate content .

As water - cement ratio is lower by 0.146 , the proportion of volume of coarse aggregate is

increased by 0.0292 ( at the rate of - / + 0.01 for every ± 0.05 change in water - cement ratio ) .

Therefore , corrected volume of coarse aggregate for the water - cement ratio of 0.354 = 0.6+.0292=0.6292

For pumpable concrete these values are reduced by 10 %

Therefore , volume of coarse aggregate = 0.6292 X 0.9 = 0.57

Volume of fine aggregate content = 1-0.57 = 0.43

VIII . Mix Calculation

1. Volume of concrete= 1m3
2. Volume of cement=(mass of cement)/(specific gravity of cement*1000)

=300/3.15*1000=0.095 m ^ 3

c. Volume of water=(mass of water)/(specific gravity of water*1000)

=152/1*1000=0.152 m ^ 3

d. Volume of Flysh ash=(mass of Flysh ash)/(specific gravity of Flysh ash *1000)

=129/2.2*1000=.0059 m ^ 3

e. Volume of Chemical admixture=(mass of Chemical admixture)/(specific gravity of Chemical admixture*1000)

i.e 1% of cementitious material

=4.29/1.145*1000=.0037 m ^ 3

f. Volume of aggregate ( FA & CA ) = ( a- ( b + c + d+e ) )

= ( 1- ( 0.095+0.152+0.0059+.0037 ) )

= 0.743 m ^ 3

g. Mass of Coarse aggregate

= ex Volume of coarse aggregate x Specific gravity of coarse aggregate X1000

=0.743 * 0.57 * 2.74 * 1000

= 1160 Kg / m ^ 3

h. Mass of fine aggregate

= ex volume of fine aggregate x specific gravity of fine aggregate x1000

= 0.743x 0.43 x 2.74 x 1000

= 875 Kg / m ^ 3

IX . Mix proportions for M30

Cement = 300 Kg / m ^ 3

Fly ash = 129 Kg / m ^ 3

Water = 152 Kg / m ^ 3

Fine aggregate = 875 Kg / m ^ 3

Coarse aggregate = 1160 Kg / m ^ 3

Chemical admixture = 4.29 Kg / m ^ 3

Water - cement ratio = 0.354

RESULT: Therefore the required mix proportion for M35 grade of concrete is Mix Ratio = 1 : 2.03 : 2.7

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Part II

Aim: To determine the design mix proportions for the M50 grade of concrete without fly ash.

Procedure: The following are the step that are used to prepare the design mix few data are assumed

I. Stipulations for proportioning

1. Grade designation : M50
2. Type of cement : OPC 43 grade conforming to IS 8112
3. Maximum nominal size of aggregate : 20mm
4. Minimum cement content : 320 kg / m ^ 3 ( From Table 5 of IS 456 : 2000 Exposure condition )
5. Maximum water - cement ratio : 0.45 ( From Table 5 of IS 456 : 2000 - Exposure condition )
6. Workability : 100 mm ( slump value for pumpable concrete )
7. Exposure condition : Severe ( for reinforced concrete )
8. Method of concrete placing : Pumping
9. Degree of supervision : Good
10. Type of aggregate : Crushed angular aggregate
11. Maximum cement content : 450 kg / m ^ 3
12. Chemical admixture type : Super plasticizer

II . Data for materials :

7. Cement used : OPC 43 grade conforming to IS 8112
8. Specific gravity of cement : 3.15
9. Chemical admixture : Super plasticizer conforming to IS 9103
10. Specific gravity of : Coarse aggregate : 2.74 , Fine aggregate: 2.74
11. Fine aggregate confirming to grading zone I of table 4 of IS383.

III . Target Strength for Mix proportioning :

f'ck fck + 1.65 S

Where , f'ck = Target average compressive strength at 28 days

fck Characteristic compressive strength at 28 days

S = Standard deviation

From Table 2 of IS 10262: 2019, standard deviation , S = 5 N / mm ^ 2

Target strength = 50 + 1.65 X 5 =58.25 N / mm ^ 2

IV . Selection of Water - cement ratio :

From Graph 1 IS10262:2019 W/C Ratio is = 0.29

From Table 5 of IS 456: 2000 for severe exposure, maximum water – content is 0.45

0.29<0.45 , hence O.K

V. Selection of Water content

From Table 4 of IS 10262 : 2019 , maximum water content for 20mm aggregate =186 litre (for 25mm to 50mm slump value)

Estimated water content for 100 mm slump = 186 + 6/100 * 186 = 197 litre

As superplasticizer is used , the water content can be reduced up to 23 %

Hence the arrived water content = 197 * 0.77 = 152 litre

VI . Calculation of Cement Content :

Water - cement ratio = 0.29

Cement content = 152 / 0.29 = 524 kg / m ^ 3

From Table 5 of IS 456 minimum cement content for severe exposure condition = 320 kg / m ^ 3

524 kg / m ^ 3 > 320 kg / m ^ 3 , Hence OK .

VII . Proportion of Volume of coarse aggregate and Fine aggregate content :

From Table 5 of IS 10262 : 2019 , Volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate ( Zone I ) for water - cement ratio of 0.5 = 0.6

In the present case the water cement ratio is 0.29

Therefore , the volume of coarse aggregate needs to be increased to decrease the fine aggregate content .

As water - cement ratio is lower by 0.21 , the proportion of volume of coarse aggregate is

increased by 0.042 ( at the rate of - / + 0.01 for every ± 0.05 change in water - cement ratio ) .

Therefore , corrected volume of coarse aggregate for the water - cement ratio of 0.29 = 0.6+.042=0.642

For pumpable concrete these values are reduced by 10 %

Therefore , volume of coarse aggregate = 0.642 X 0.9 = 0.578

Volume of fine aggregate content = 1-0.578 = 0.422

VIII . Mix Calculation

a. Volume of concrete= 1m3

b. Volume of cement=(mass of cement)/(specific gravity of cement*1000)

=524/3.15*1000=0.166 m ^ 3

c. Volume of water=(mass of water)/(specific gravity of water*1000)

=152/1*1000=0.152 m ^ 3

d. Volume of Chemical admixture=(mass of Chemical admixture)/(specific gravity of Chemical admixture*1000)

i.e 1% of cementitious material

=5.24/1.145*1000=.0046 m ^ 3

e. Volume of aggregate ( FA & CA ) = ( a- ( b + c + d ) )

= ( 1- ( 0.166 + 0.152 + 0.0046 ) )

= 0.6774 m ^ 3

f. Mass of Coarse aggregate

= ex Volume of coarse aggregate x Specific gravity of coarse aggregate X1000

=0.6774 * 0.578 * 2.74 * 1000

= 1073 Kg / m ^ 3

g. Mass of fine aggregate

= ex volume of fine aggregate x specific gravity of fine aggregate x1000

= 0.6774 x 0.422 x 2.74 x 1000

= 783 Kg / m ^ 3

IX . Mix proportions for M30

Cement = 524 Kg / m ^ 3

Water = 152 Kg / m ^ 3

Fine aggregate = 783 Kg / m ^ 3

Coarse aggregate = 1073 Kg / m ^ 3

Chemical admixture = 5.24 Kg / m ^ 3

Water - cement ratio = 0.29

RESULT : Therefore the required mix proportion for M50 grade of concrete is Mix Ratio = 1 : 1.49 : 2.04